JP2004186138A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to distribute a reaction gas well throughout the electrode face by making uniform the flow-path resistance in a zigzag reaction gas passage. <P>SOLUTION: An oxidizer gas passage 32 for supplying an oxidizer gas from an oxidizer gas entrance communicating hole 20a to an oxidizer gas exit communicating hole 20b is formed on a first metal plate 14. This oxidizer gas passage 32 comprises oxidant gas passage grooves 38a-38c which constitute serpentine passage grooves having two turning over portions T1, T2. The length of each passage of the oxidizer gas passage grooves 38a-38c is established nearly same and an entrance buffer part 34 and an exit buffer part 36 are communicated at both ends. The entrance buffer part 34 and the exit buffer part 36 have nearly a triangular form and are constituted in nearly a symmetrical shape. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a fuel cell having an electrolyte / electrode structure formed by sandwiching an electrolyte between a pair of electrodes, and alternately stacking the electrolyte / electrode structure and a separator.

  For example, a polymer electrolyte fuel cell employs a polymer electrolyte membrane composed of a polymer ion exchange membrane (cation exchange membrane). In this fuel cell, on both sides of a solid polymer electrolyte membrane, an electrolyte membrane / electrode structure (electrolyte / electrode structure) having an anode electrode and a cathode electrode made of an electrode catalyst and porous carbon, respectively, are provided. It is configured by being sandwiched between separators (bipolar plates). Usually, a fuel cell stack in which a predetermined number of the fuel cells are stacked is used.

  In this type of fuel cell, a fuel gas (reactive gas) supplied to the anode electrode, for example, a gas mainly containing hydrogen (hereinafter, also referred to as a hydrogen-containing gas) is ionized with hydrogen on the electrode catalyst, It moves to the cathode side via the electrolyte membrane. The electrons generated during that time are taken out to an external circuit and used as DC electric energy. Note that an oxidizing gas (reactive gas), for example, a gas mainly containing oxygen or air (hereinafter, also referred to as an oxygen-containing gas) is supplied to the cathode side electrode. Hydrogen ions, electrons and oxygen react to produce water.

  In the above fuel cell, a fuel gas flow path (reactive gas flow path) for flowing a fuel gas opposite to the anode electrode and an oxidizing gas for flowing the fuel gas opposite the cathode electrode are formed in the surface of the separator. Oxidant gas flow path (reaction gas flow path). Further, between the separators, a cooling medium flow path for flowing a cooling medium is provided along the surface direction of the separator. The fuel gas flow path, the oxidizing gas flow path, and the cooling medium flow path generally have a plurality of flow grooves provided from the flow path inlet communication hole penetrating in the stacking direction of the separators to the flow path outlet communication hole. In addition to this, the flow channel is formed of a straight groove or a folded flow channel.

  However, when a small channel inlet communication hole or a channel outlet communication hole with an opening is provided for the plurality of channel grooves, a fluid such as a fuel gas, an oxidizing gas, or a cooling medium is provided along the channel grooves. In order to flow smoothly, a buffer portion is required around the flow path inlet communication hole and the flow path outlet communication hole.

  Therefore, for example, a gas passage plate of a fuel cell disclosed in Patent Document 1 is known. In Patent Document 1, as shown in FIG. 11, for example, a gas passage plate 1 on the oxidizing gas side includes a groove member 2 made of carbon or metal. An oxidant gas inlet manifold 3 is provided on the upper side of the gas passage plate 1, and an oxidant gas outlet manifold 4 is formed on the lower side of the gas passage plate 1.

  The groove member 2 has an inlet-side communication groove 5a communicating with the inlet manifold 3, an outlet-side communication groove 5b communicating with the outlet manifold 4, the inlet-side communication groove 5a, and the outlet-side communication groove 5b. And an intermediate communication groove 6 that communicates with. The inlet-side communication groove 5a and the outlet-side communication groove 5b are formed in a lattice shape through a plurality of protrusions 7a, while the intermediate communication groove 6 is formed in a bent shape that is bent a plurality of times. It has a linear groove portion 8 and a lattice-shaped groove portion 9 formed by a plurality of protrusions 7b at a folded portion.

  In the gas passage plate 1 of the fuel cell configured as described above, the inlet-side flow groove 5a and the outlet-side flow groove 5b constitute a buffer portion, and the contact area of the supply gas with the electrode is increased. The supply gas can move freely, while the intermediate flow groove 6 allows the reaction gas to flow uniformly at high speed through the plurality of linear grooves 8.

JP-A-10-106594 (FIG. 1)

  In this case, a plurality of meandering flow paths (serpentine flow paths) 1a from the inlet manifold 3 to the outlet manifold 4 are actually formed in the gas passage plate 1 described above. At that time, in the plurality of linear grooves 8, the lengths of the respective flow paths 1a are substantially the same, and the respective flow path resistances tend to be constant.

  However, in the inlet-side communication groove 5a and the outlet-side communication groove 5b formed in a lattice shape through the plurality of protrusions 7a, each flow path 1a from the inlet manifold 3 and the outlet manifold 4 to each linear groove 8 is formed. Have different lengths. As a result, the flow path resistance in the inlet-side flow groove 5a and the outlet-side flow groove 5b fluctuates, so that the reaction gas cannot be supplied uniformly over the entire electrode surface, and the distribution of the reaction gas decreases. Has been pointed out.

  On the other hand, also in the grid-like groove 9 formed by the plurality of protrusions 7b, similarly, the reaction gas introduced into each linear groove 8 after being led out from each linear groove 8 to the lattice-like groove 9 and turned back, Since the lengths of the respective flow paths 1a are different, uniform distribution cannot be maintained. For this reason, it becomes difficult to uniformly supply the reaction gas over the entire electrode surface, and there is a problem that desired power generation performance cannot be secured.

  The present invention is intended to solve this kind of problem, and can equalize the flow path resistance in the meandering reaction gas flow path, distribute the reaction gas satisfactorily over the entire electrode surface, and obtain good power generation performance. It is an object of the present invention to provide a fuel cell capable of ensuring the above.

  In the fuel cell of the present invention, the reaction gas flow path for supplying the reaction gas along the surface direction of the electrode includes a plurality of serpentine flow grooves having substantially the same length and having an even number of turns in the separator surface. ing. Further, the reaction gas flow path has a substantially triangular inlet buffer portion communicating with the serpentine flow channel in a reaction gas inlet communication hole penetrating in the stacking direction, and the reaction gas outlet communication hole in the stacking direction. A substantially triangular outlet buffer portion communicating with the flow channel is provided, and the inlet buffer portion and the outlet buffer portion are configured to be substantially symmetrical to each other.

  Further, it is preferable that a plurality of embosses are provided in at least one of the inlet buffer section and the outlet buffer section.

  Further, the reaction gas inlet communication hole and the reaction gas outlet communication hole are provided with at least one oblique side, and the oblique side of the reaction gas inlet communication hole faces the inclined portion of the inlet buffer section, while the reaction gas outlet It is preferable that the oblique side of the communication hole is opposed to the inclined portion of the outlet buffer.

  Furthermore, it is preferable that one side of the inlet buffer section and one side of the outlet buffer section are substantially orthogonal to the end of the serpentine flow channel.

  In the fuel cell according to the present invention, since the serpentine flow grooves forming the reaction gas flow path have substantially the same flow path length, the flow path resistance is made uniform, and the respective serpentine flow paths are formed. The reaction gas can be uniformly supplied to the channel. Furthermore, a substantially triangular inlet buffer portion and a substantially triangular outlet buffer portion constituting a reaction gas flow path are provided, and the inlet buffer portion and the outlet buffer portion are configured to be substantially symmetric with each other. .

  Therefore, the flow resistance of the entire reaction gas flow path from the reaction gas inlet communication hole to the reaction gas outlet communication hole is made uniform, and the distribution of the reaction gas in the reaction gas flow path is further improved. This makes it possible to maintain the power generation performance of the fuel cell effectively.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to an embodiment of the present invention, and FIG. 2 is a partially sectional explanatory view of the fuel cell 10.

  The fuel cell 10 is configured by alternately laminating an electrolyte membrane / electrode structure (electrolyte / electrode structure) 12 and a separator 13, and the separator 13 is composed of first and second metal plates laminated on each other. 14 and 16 are provided.

  As shown in FIG. 1, an oxidizing gas (reactive gas), for example, an oxygen-containing gas is supplied to one end of the fuel cell 10 in the direction of arrow B in communication with the direction of arrow A, which is the stacking direction. Gas inlet communication hole (reaction gas inlet communication hole) 20a for supplying a cooling medium, and a cooling medium inlet communication hole 22a for supplying a cooling medium, and fuel for discharging a fuel gas (reaction gas), for example, a hydrogen-containing gas. Gas outlet communication holes (reaction gas outlet communication holes) 24b are arranged in the direction of arrow C (vertical direction).

  The other end portions of the fuel cell 10 in the direction of arrow B communicate with each other in the direction of arrow A to discharge a fuel gas inlet communication hole (reaction gas inlet communication hole) 24a for supplying fuel gas and a cooling medium. Medium outlet communication holes 22b for discharging the oxidizing gas and oxidizing gas outlet communication holes (reaction gas outlet communication holes) 20b for discharging the oxidizing gas are arranged in the arrow C direction.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 26 in which a thin film of perfluorosulfonic acid is impregnated with water, an anode electrode 28 and a cathode electrode sandwiching the solid polymer electrolyte membrane 26. 30.

  The anode-side electrode 28 and the cathode-side electrode 30 are composed of a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly coated on the surface of the gas diffusion layer. Respectively. The electrode catalyst layers are joined to both surfaces of the solid polymer electrolyte membrane 26 so as to face each other with the solid polymer electrolyte membrane 26 interposed therebetween.

  As shown in FIGS. 1 and 3, an oxidizing gas flow path (reactive gas flow path) 32 is provided on a surface 14 a of the first metal plate 14 on the side of the electrolyte membrane / electrode structure 12. The gas passage 32 communicates with the oxidizing gas inlet communication hole 20a and the oxidizing gas outlet communication hole 20b. The oxidizing gas passage 32 is provided near the oxidizing gas outlet communicating hole 20b, and has a substantially right triangle (substantially triangular) inlet buffer 34 provided near the oxidizing gas inlet communicating hole 20a. A substantially right triangular exit buffer 36 (substantially triangular). The inlet buffer section 34 and the outlet buffer section 36 are configured to be substantially symmetrical with each other, and are provided with a plurality of embosses 34a, 36a.

  The inlet buffer section 34 and the outlet buffer section 36 communicate with each other via three oxidant gas flow grooves 38a, 38b, and 38c. The oxidizing gas channel grooves 38a to 38c extend in the direction of arrow C while meandering in the direction of arrow B in parallel with each other. Specifically, as the oxidizing gas flow grooves 38a to 38c, a serpentine flow groove having one and a half reciprocation in the direction of arrow B having an even number of times, for example, two turns T1 and T2 is formed. Thereby, the lengths of the respective flow paths are set to substantially the same length.

  As shown in FIG. 3, the vertical portion (one side) 34b of the inlet buffer portion 34 is arranged in the direction of arrow C, and is substantially orthogonal to the terminal portions of the oxidizing gas flow grooves 38a to 38c. The inclined part 34c of the buffer part 34 is arranged toward the oxidant gas inlet communication hole 20a. Various shapes such as a square, a parallelogram or a trapezoid are selected for the oxidizing gas inlet communication hole 20a, and an inner wall surface forming the oxidizing gas inlet communication hole 20a has an inlet buffer portion 34. An oblique side 37a facing and parallel to the inclined portion 34c is provided.

  The shape of the oxidizing gas inlet communication hole 20a is variously selected as described above, and the projecting portions 39a and 39b bulging toward the oxidizing gas inlet communication hole 20a may be provided. Hereinafter, the oxidizing gas outlet communication hole 20b, the fuel gas inlet communication hole 24a, and the fuel gas outlet communication hole 24b are also configured in the same manner as the oxidizing gas inlet communication hole 20a.

  The vertical portion (one side) 36b of the outlet buffer portion 36 is disposed toward the direction of arrow C, is substantially orthogonal to the end portions of the oxidizing gas flow grooves 38a to 38c, and has the oxidizing gas flow grooves 38a to 38c. 38c is regulated to have substantially the same length between the vertical portions 34b and 36b. The inclined portion 36c of the outlet buffer portion 36 is arranged to face the oxidant gas outlet communication hole 20b. An oblique side 37b parallel to the inclined portion 36c is provided on the inner wall surface forming the oxidant gas outlet communication hole 20b.

  On the surface 14a of the first metal plate 14, a linear seal 40 that seals the oxidizing gas by covering the oxidizing gas inlet communication hole 20a, the oxidizing gas outlet communication hole 20b, and the oxidizing gas flow path 32 is provided. .

  A cooling medium channel 42 is integrally formed on the opposing surfaces 14b and 16a of the first metal plate 14 and the second metal plate 16. As shown in FIG. 4, the cooling medium flow path 42 is provided in the vicinity of both ends of the cooling medium inlet communication hole 22 a in the direction of the arrow C, and includes, for example, first and second substantially triangular inlet buffer sections 44 and 46. For example, first and second outlet buffer portions 48 and 50 having a substantially triangular shape are provided near both ends of the cooling medium outlet communication hole 22b in the direction of arrow C.

  The first inlet buffer section 44 and the second outlet buffer section 50 are configured to be substantially symmetrical to each other, and the second inlet buffer section 46 and the first outlet buffer section 48 are formed to be substantially symmetrical to each other. Is configured. The first inlet buffer section 44, the second inlet buffer section 46, the first outlet buffer section 48, and the second outlet buffer section 50 are constituted by a plurality of embosses 44a, 46a, 48a and 50a.

  The cooling medium inlet communication hole 22a and the first and second inlet buffer sections 44 and 46 communicate with each other through the first and second inlet communication flow paths 52 and 54, while the cooling medium outlet communication hole 22b and the first The first and second outlet buffers 48 and 50 communicate with the first and second outlet communication channels 56 and 58, respectively. The first inlet communication channel 52 includes, for example, two channel grooves, and the second inlet communication channel 54 includes, for example, six channel grooves. Similarly, the first outlet communication channel 56 has six channel grooves, while the second outlet communication channel 58 has two channel grooves.

  The number of flow paths of the first inlet communication flow path 52 and the number of flow paths of the second inlet communication flow path 54 are not limited to two and six. The same may be set. The same applies to the first and second outlet communication channels 56, 58.

  The first inlet buffer section 44 and the first outlet buffer section 48 communicate with each other via linear flow grooves 60, 62, 64 and 66 extending in the direction of arrow B, and the second inlet buffer section. The second outlet buffer section 50 communicates with the second outlet buffer section 50 via straight flow channel grooves 68, 70, 72 and 74 extending in the direction of arrow B. Between the straight flow grooves 66, 68, straight flow grooves 76, 78 are provided extending a predetermined length in the direction of arrow B.

  The straight channel grooves 60 to 74 communicate with each other via straight channel grooves 80 and 82 extending in the arrow C direction. The straight flow grooves 62 to 78 communicate with the straight flow grooves 84 and 86 extending in the direction of arrow C, and the straight flow grooves 64, 66 and 76 and the straight flow grooves 68, 70 and 78 communicate with each other through linear flow grooves 88 and 90 intermittently extending in the direction of arrow C.

  The cooling medium flow path 42 is divided into a first metal plate 14 and a second metal plate 16. By overlapping the first and second metal plates 14 and 16 with each other, the cooling medium flow path 42 is formed. It is formed. As shown in FIG. 5, a part of the cooling medium channel 42 is formed on the surface 14b of the first metal plate 14 so as to avoid the oxidizing gas channel 32 formed on the surface 14a side.

  Although the oxidizing gas flow path 32 formed on the surface 14a protrudes in a convex shape on the surface 14b, illustration of the convex portion is omitted for easy understanding of the cooling medium flow path 42. . Similarly, in the surface 16a shown in FIG. 6, a portion where a fuel gas flow channel (reaction gas flow channel) 96 formed on the surface 16b, which will be described later, protrudes in a convex shape from the surface 16a is omitted.

  The surface 14b has a first inlet buffer portion 44 that communicates with the cooling medium inlet communication hole 22a through two first inlet communication flow paths 52, and two second buffer holes that communicate with the cooling medium outlet communication hole 22b. A second outlet buffer unit 50 communicating with the outlet communication channel 58 is provided.

  Grooves 60a, 62a, 64a and 66a are intermittently arranged in the direction of arrow B in the first inlet buffer section 44 so as to avoid the turn-back portion T2 of the oxidizing gas passage grooves 38a to 38c and the outlet buffer section 36. The target is provided at a predetermined length. In the second outlet buffer section 50, grooves 68a, 70a, 72a, and 74a are provided along the arrow B direction so as to avoid the turn-back portion T1 of the oxidizing gas flow channel grooves 38a to 38c and the inlet buffer section 34. Is provided at the position.

  The grooves 60a to 78a form part of the linear flow grooves 60 to 78, respectively. The groove portions 80a to 90a constituting the straight flow channel grooves 80 to 90 are respectively provided over predetermined lengths in the direction of arrow C so as to avoid the meandering oxidizing gas flow channel grooves 38a to 38c.

  As shown in FIG. 6, a part of the cooling medium flow path 42 is formed on the surface 16a of the second metal plate 16 so as to avoid a fuel gas flow path 96 described later. Specifically, a second inlet buffer section 46 communicating with the cooling medium inlet communication hole 22a and a first outlet buffer section 48 communicating with the cooling medium outlet communication hole 22b are provided.

  While the groove portions 68b to 74b constituting the linear flow channel grooves 68 to 74 communicate with the second inlet buffer portion 46 at a predetermined length and intermittently in the direction of arrow B, the first outlet buffer portion Grooves 60b to 66b constituting the linear flow grooves 60 to 66 are set in a predetermined shape and communicate with the portion 48. On the surface 16a, grooves 80b to 90b constituting the linear flow grooves 80 to 90 are provided extending in the direction of arrow C.

  In the cooling medium flow channel 42, a part of the linear flow channels 60 to 78 extending in the direction of arrow B has a different flow channel cross-sectional area due to the respective grooves 60a to 78a and 60b to 78b facing each other. The main flow path is configured to be twice as large as the part (see FIG. 4). The straight channel grooves 80 to 90 are partially overlapped and distributed to the first and second metal plates 14 and 16, respectively. Between the surface 14a of the first metal plate 14 and the surface 16a of the second metal plate 16, a linear seal 40a surrounding the cooling medium flow path 42 is interposed.

  As shown in FIG. 7, a fuel gas flow path 96 is provided on a surface 16 b of the second metal plate 16 on the side of the electrolyte membrane / electrode structure 12. The fuel gas flow path 96 includes a substantially right triangle (substantially triangular) inlet buffer 98 provided near the fuel gas inlet communication hole 24a, and a substantially right triangle provided near the fuel gas outlet communication hole 24b. And an outlet buffer unit 100 having a substantially triangular shape.

  The inlet buffer section 98 and the outlet buffer section 100 are configured to be substantially symmetrical with each other, and are provided with a plurality of embosses 98a, 100a, for example, via three fuel gas flow grooves 102a, 102b, and 102c. Communicate. The fuel gas flow grooves 102a to 102c extend in the direction of the arrow C while meandering in the direction of the arrow B, and are provided with an even number of times, for example, two turn-back portions T3 and T4, and are substantially one and a half times reciprocating. By being formed in the serpentine channel groove, the respective channel lengths are set to be substantially the same.

  The vertical portion (one side) 98b of the inlet buffer portion 98 is disposed in the direction of arrow C, and is substantially orthogonal to the end portions of the fuel gas flow grooves 102a to 102c, and the inclined portion 98c is connected to the fuel gas inlet communication hole 24a. It is arranged toward. An oblique side 104a facing the inclined portion 98c and parallel to the inclined portion 98c is formed on the inner wall surface of the fuel gas inlet communication hole 24a. The vertical portion (one side) 100b of the outlet buffer portion 100 is arranged in the direction of arrow C, and is substantially orthogonal to the end portions of the fuel gas flow grooves 102a to 102c, and the inclined portion 100c is connected to the fuel gas outlet communication hole 24b. They are arranged facing each other. An oblique side 104b parallel to the inclined portion 100c is formed on an inner wall surface of the fuel gas outlet communication hole 24b. A linear seal 40b surrounding the fuel gas flow path 96 is provided on the surface 16b.

  The operation of the fuel cell 10 according to this embodiment configured as described above will be described below.

  As shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a, and an oxidizing gas such as an oxygen-containing gas is supplied to the oxidizing gas inlet communication hole 20a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  The oxidizing gas is introduced into the oxidizing gas passage 32 of the first metal plate 14 from the oxidizing gas inlet communication hole 20a. In the oxidizing gas passage 32, as shown in FIG. 3, after the oxidizing gas is once introduced into the inlet buffer portion 34, it is dispersed in the oxidizing gas passage grooves 38a to 38c. Therefore, the oxidizing gas moves along the cathode 30 of the electrolyte membrane / electrode structure 12 while meandering through the oxidizing gas flow grooves 38a to 38c.

  On the other hand, the fuel gas is introduced into the fuel gas passage 96 of the second metal plate 16 from the fuel gas inlet communication hole 24a. In the fuel gas passage 96, as shown in FIG. 7, after the fuel gas is once introduced into the inlet buffer 98, it is dispersed into the fuel gas passage grooves 102a to 102c. Further, the fuel gas meanders through the fuel gas flow grooves 102 a to 102 c and moves along the anode 28 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidizing gas supplied to the cathode 30 and the fuel gas supplied to the anode 28 are consumed by the electrochemical reaction in the electrode catalyst layer, and the power is generated. Is performed.

  Next, the fuel gas supplied to the anode 28 and consumed is discharged from the outlet buffer unit 100 to the fuel gas outlet communication hole 24b. Similarly, the oxidant gas supplied to and consumed by the cathode 30 is discharged from the outlet buffer 36 to the oxidant gas outlet communication hole 20b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium passage 42 formed between the first and second metal plates 14 and 16. In the cooling medium flow path 42, as shown in FIG. 4, the first and second cooling medium flow paths 42 and 54 extend through the first and second inlet communication flow paths 52 and 54 extending in the direction of arrow C from the cooling medium inlet communication hole 22a. The cooling medium is once introduced into the inlet buffer portions 44 and 46 of the cooling medium.

  The cooling medium introduced into the first and second inlet buffers 44 and 46 is dispersed in the linear flow grooves 60 to 66 and 68 to 74 and moves in the horizontal direction (the direction of arrow B). The parts are supplied to the linear flow grooves 80-90 and 76,78. Therefore, after the cooling medium is supplied over the entire power generation surface of the electrolyte membrane / electrode structure 12, the cooling medium is once introduced into the first and second outlet buffer sections 48, 50, and further, the first and second outlet communication flows. The cooling medium is discharged to the cooling medium outlet communication hole 22b through the passages 56 and 58.

  In this case, in the present embodiment, as shown in FIG. 7, the fuel gas flow channel 96 includes three fuel gas flow channel grooves 102a to 102c having two folded portions T3 and T4 in the surface 16b, The flow path lengths of the fuel gas flow grooves 102a to 102c are set to be substantially the same. For this reason, the flow resistance of the fuel gas in the fuel gas flow grooves 102a to 102c is made uniform, and the fuel gas can be uniformly supplied along the fuel gas flow grooves 102a to 102c.

  Further, the fuel gas flow path 96 includes an inlet buffer section 98 and an outlet buffer section 100 each having a substantially triangular shape, and the inlet buffer section 98 and the outlet buffer section 100 are configured to be substantially symmetrical to each other. I have. Therefore, as shown in FIG. 8, on both sides of the fuel gas flow grooves 102a to 102c, the sum of the flow resistance of the inlet buffer 98 and the flow resistance of the outlet buffer 100 is substantially the same. I have.

  As a result, the flow resistance of the entire fuel gas passage 96 from the fuel gas inlet communication hole 24a to the fuel gas outlet communication hole 24b is made uniform, and the fuel gas distribution property in the fuel gas flow passage 96 is further improved. I do. Therefore, an effect is obtained that the fuel gas can be supplied uniformly and reliably over the entire electrode surface of the anode 28.

  In addition, the inlet buffer section 98 and the outlet buffer section 100 are provided with a plurality of embosses 98a, 100a. Therefore, the fuel gas can be uniformly distributed, and the strength can be improved, so that the adjacent electrolyte membrane / electrode structure 12 can be reliably supported.

  Further, since the entrance buffer section 98 and the exit buffer section 100 are formed in a substantially triangular shape, the area can be reduced as compared with a conventional rectangular buffer section. As a result, the area occupied by the inlet buffer section 98 and the outlet buffer section 100 is effectively reduced, and the separator 13 can be easily reduced in size.

  Furthermore, the inclined portions 98c, 100c of the inlet buffer portion 98 and the outlet buffer portion 100 face the oblique sides 104a, 104b of the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b and are parallel to the inclined portions 98c, 100c. are doing. Therefore, it is possible to secure a good cross-sectional area of the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b with a compact configuration.

  Further, the vertical portions 98b and 100b of the inlet buffer portion 98 and the outlet buffer portion 100 are substantially orthogonal to the end portions of the fuel gas flow grooves 102a to 102c. Therefore, the fuel gas can flow smoothly from the inlet buffer 98 to the fuel gas flow grooves 102a to 102c, and the fuel gas can flow smoothly from the fuel gas flow grooves 102a to 102c to the outlet buffer 100. It becomes possible.

  On the other hand, as shown in FIG. 3, in the oxidizing gas flow path 32, similarly to the fuel gas flow path 96, three oxidizing gas flow grooves 38 a to 38 c have serpentine flows having substantially the same length. It constitutes a road channel. Further, the inlet buffer section 34 and the outlet buffer section 36 provided at both ends of the oxidizing gas flow channel grooves 38a to 38c are formed in a substantially triangular shape and a substantially symmetric shape with each other.

  Therefore, the flow resistance of the entire oxidizing gas passage 32 from the oxidizing gas inlet communication hole 20a to the oxidizing gas outlet communication hole 20b is reliably made uniform, and the distribution of the oxidizing gas in the oxidizing gas passage 32 is ensured. The performance is effectively improved. Therefore, the oxidant gas can be supplied uniformly and reliably over the entire electrode surface of the cathode 30. Thereby, an advantage that the power generation performance of the fuel cell 10 can be effectively maintained can be obtained.

  The oxidizing gas flow grooves 38a to 38c and the fuel gas flow grooves 102a to 102c constitute a one-and-a-half reciprocating serpentine flow groove having two folded portions, but are not limited thereto. Instead, it is only necessary to have an even number of turns, such as four or six times.

  In the present embodiment, the substantially triangular buffer unit is described using, for example, the entrance buffer unit 34, but the present invention is not limited to this. The entrance buffer unit 120 shown in FIG. 9 has a substantially triangular shape (including a substantially trapezoidal shape) having a bottom side 120a and an upper side 120b. On the other hand, the entrance buffer unit 130 shown in FIG. 10 is configured in a substantially triangular shape having an inclined bottom 130a.

FIG. 2 is an exploded perspective view of a main part of the fuel cell according to the embodiment of the present invention. FIG. 2 is a partially sectional explanatory view of the fuel cell. It is front explanatory drawing of one surface of a 1st metal plate. It is a perspective explanatory view of a cooling medium channel formed in a separator. It is a front explanatory view of the other surface of the first metal plate. It is front explanatory drawing of a 2nd metal plate. It is front explanatory drawing of the other surface of the said 2nd metal plate. FIG. 4 is a diagram illustrating a relationship between a position of a fuel gas flow path and a flow path resistance. It is explanatory drawing of the entrance buffer part which has another shape. It is explanatory drawing of the entrance buffer part which has another shape. FIG. 9 is an explanatory view of a gas passage plate of the fuel cell of Patent Document 1.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Electrolyte membrane / electrode structure 13 ... Separator 14, 16 ... Metal plate 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication Hole 24a: fuel gas inlet communication hole 24b: fuel gas outlet communication hole 26 ... solid polymer electrolyte membrane 28 ... anode side electrode 30 ... cathode side electrode 32 ... oxidant gas flow path 34, 44, 46, 98, 120, 130 ... Inlet buffer portions 36, 48, 50, 100. Outlet buffer portions 38a to 38c. Oxidant gas flow channel 42. Coolant flow channel 96. Fuel gas flow channel 102a to 102c.

Claims (4)

An electrolyte / electrode structure comprising an electrolyte sandwiched between a set of electrodes, the electrolyte / electrode structure and a separator are alternately stacked, and a reaction gas inlet communication hole and a reaction gas penetrating in the stacking direction. A fuel cell in which a gas outlet communication hole is formed,
A reaction gas flow path for supplying a reaction gas along the surface direction of the electrode,
The reaction gas flow path, a plurality of substantially the same length serpentine flow grooves having an even number of turns in the separator surface,
A substantially triangular inlet buffer unit that communicates the serpentine flow channel with the reaction gas inlet communication hole;
A substantially triangular outlet buffer portion communicating the serpentine flow channel with the reaction gas outlet communication hole,
With
The fuel cell according to claim 1, wherein the inlet buffer section and the outlet buffer section are substantially symmetrical to each other.   2. The fuel cell according to claim 1, wherein a plurality of embosses are provided on at least one of the inlet buffer section and the outlet buffer section. 3. The fuel cell according to claim 1, wherein the reaction gas inlet communication hole and the reaction gas outlet communication hole have at least one oblique side, and
The fuel according to claim 1, wherein the oblique side of the reaction gas inlet communication hole faces the inclined portion of the inlet buffer portion, while the oblique side of the reaction gas outlet communication hole faces the inclined portion of the outlet buffer portion. battery. 4. The fuel cell according to claim 1, wherein one side of the inlet buffer and one side of the outlet buffer are substantially orthogonal to a terminal end of the serpentine flow channel. 5. Fuel cell.

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